<?php
/**
  * ZERO
  *
  * This is not a freeware, use is subject to license terms
  * @author ZERO DEV TEAM
  * 
  */
class PictureTag extends Model
{
	
	private static $object;
	
	private function PictureTag()
	{
		$this->tableName = 'picture_tag';
		parent::__construct();
	}
	
	public static function getInstance()
	{
		if ( !is_object( self::$object ) )
		{
			self::$object = new self();
		}
		return self::$object;
	}
	
	/**
	 * 检验此tag是否存在
	 * @param string $tag
	 */
	public function checkIsExists( $tag )
	{
		return $this->getOne( array( 'tag_content' => $tag ) );
	}
}